Lubricant and method of making same



Patented Dec. 29, 1953 LUBRICANT AND, METHOD OF MAKING SAME John D. Bartleson, Cleveland, Ohio, as'slgnor to The Standard Oil Company, Cleveland, Ohio,

a corporation of Ohio No Drawing. Application December 22, 1949, Serial No. 134,621

This invention relates to a method of improving the color of lubricants and lubricant additives which are reaction products of 5 to 60% by weight or a phosphorus sulfide and 95 to 40% of a mixture of one part by weight of an oxygen-contain- 'ing organic compound having a boiling point of at least 225 F. with 1 to parts of a poly-olefin capable of improving the viscosity index characteristic of a lubricatingoil, reacted together at a temperature in the range of 225 to 500 R; which method essentially comprises treating such reaction products with a decolorizing agent having a critically low water content in the range of 0 to 6% by weight in an amount in the range of 1 to 10% by weight of the reaction mixture and sufiicient to improve the color of the reaction products; The invention also relates to the resulting improved lubricants and lubricant additives.

The patent of John M. Musselman, Patent No. 2,566,241, filed May 27,1948, issued August 2 1951, discloses highly advantageous lubricants and lubricant additives which are prepared by reacting a poly-olefin (viscosity index improvement ad-' 'ditive) with an oxygenated organic compound having a boiling point of at least 225 F. (such as degras) and a phosphorus sulfide (such as Piss). These reactants are reacted together at a temperature in the range of 225 to 500 F.

Lubricants prepared in accordance with the invention are suitable for use under various conditions, including high temperatures or high pressure or both; as, for instance, use in an internal combustoin engine operating at high temperatures and in which the lubricant is in close contact with metallic surfaces, metal compounds and high temperature gases. They are also suitable as extreme pressure lubricant agents in oils and greases.

The present invention is directed to the improvement of the above described reaction products, especially as to color, by treatment with a decolorizing agent containing a critically low proportion of water. This improvement is ofgreat commercial importance because the public de- "sires "a light colored lubricating oil; and the performance of the product is distinctly superior to that of products obtained by usual treatment, e. g., with clays which have a higher water con-- tent, e. g., about or more, especially after storage.

The objects achieved in accordance with the invention include the provision of an improved agent which may be useful itself as a lubricant, and. which when added to lubricants willimprove the viscosity index and also markedly inhibit the 8 Claims. (Cl. 21042;5')

very objectionable deposition of lacquer, and, at

the same time, inhibit acid and sludge formation, corrosion and other types of deterioration occurring under operating conditions; the provision of lubricating oils containing such an addition agent; and other objects which will be apparent as embodiments of the invention are disclosedhereinafter.

The reaction product may be made with direct admixture of the reactants, or, if desired, by their admixture in the presenceof a diluent which may or may not be subsequently removed. A heavy oil such as 'white oil, or a lubricating oil having about the same properties as that to which the new composition is to be added may be used as a diluent. Oil may be added after the reaction such as during a subsequent filtration. The reaction is usually complete in about 10 hours or less time, generally 1 to -2 hours. The reaction time is a function of the temperature, the amount of the sulfide that is to react, the subdivision of the reactants, the efiiciencyof mixing, etc.

The mixture of poly-olefin and oxygen-containing organic compound may be reacted with the phosphorus sulfide or a mixture of phosphorus sulfides in ratios from 5 to about weight per centof the phosphorus sulfide based on the weight of the above mixture, depending on the type of mixture. Generally about 10 toabout 50 per cent is the usual range that will be used, depending on the molecular weight of the poly-olefin and its proportions relative to the oxygen-containing organic compound, and about 10 to about 20 per cent is especially desirable.

Phosphorus penta'sulfide is preferred although other phosphorus sulfides or mixtures of sulfides may be employed. Phosphorus pentasulfide "is most economic and readily available and for this reason is used in the illustrative examples.

The poly-olefin which may be used is one which improves the viscosity index of lubricating oil, e. g., one having a molecular weight of about 2,000 to 100,000 and which is soluble in lubricating oil. These materials are substantially saturated as the art will appreciate. As mentioned above, such materials are known in the art. The commericaliy available material is known as Paratone which is a polyisobutylene polymer of 10,000 to 20,000 molecular weight in such amount in a solution or oil as to give a viscosity of about 3,000 S. S. U. at 210 F.

An ester wax such as degras, lanolin or sperm oil is a preferred oxygen-containing organic compound; In the broader aspects of the invention, there may be used such a compound containing hydroxy, carbonyl, or ether oxygen, and desirably one of rather high molecular weight, preferably boiling above the reaction temperature, e. g. at least 225 F. The reaction may be conducted under pressure, if desired, in the case of lower boiling materials. There may be used esters, as alkyl or cycloparafiin or aryl esters of organic acids; fatty oils, higher alcohols, higher carboxylic acids, saturated and unsaturated, mono-basic and dibasic, petroleum acids, naphthenic acid, rosin, modified rosin, glycol ethers, higher ketones and aldehydes; also halogenated derivatives of any of these. Illustrative of some conveniently applicable materials are: beeswax, lanolin, sperm oil, other waxes, butyl stearate, ethyl lactate, methyl oleate, butyl ricinoleate, butyl phthalate, methyl stearate, methyl dichlorostearate, methyl chloro-naphthenate, di-

chloropalmitic acid, coconut oil, babassu oil, hy-

drogenated coconut and other vegetable oils, other fatty oils, ethylene glycol mono ethers, diglycol chloro-hydrin, lauryl alcohol, stearic acid, lauric acid, oleic acid, palmitic acid, myristic acid,

naphthalic acid, naphthoic acid, benzoic acid, naphthenic acids, hydroxystearic acid, dihydroxybenzoic acids, hydroxynaphthenic acids, dihydroxystearic acid, chlorobenzoic acid, dichlorostearic acids, dichlorobenzoic acid, dichlorodihydroxystearic acid, lactones, palmitone, oxidized petroleum fatty acid or other petroleum product, as oxidized wax, kerosene, gas oil or other oxidized petroleum oil. The oxygenated compound used in forming the reaction product should be selected with reference to the use of the final composition and properties desired in it, e. g., to give a reaction product having oil solubility or dispersibility.

In the illustrative embodiment it is preferred to use about 3 parts by weight of the poly-isobutylene oil solution available as Paratone with about one part by weight of the degras or other oxygenated organic material. If the ,Paratone is assumed to be a 40% to 50% solution in oil, this would be about 1.2 to 1.5 parts of the poly-isobutylene to one part of degras. However, widely different proportions show significant improvements and an amount of polyolefin in the range of 1 to parts by weight to one part of the oxygenated material is desirable.

The reaction may be carried out in the presence or absence of air, or in the atmosphere of inert or non-deleterious gas, such as nitrogen or H28. It may also be carried out under pressure, e. g., the pressure generated when the reaction is carried out in a closed vessel.

The reaction temperature varies with polyolefin and oxygen-containing compound and is readily ascertained. The optimum is in the range of 225 to 500 F., although a higher temperature which is below that at which the reaction product would be decomposed could be used. A temperature of at least 250 to 300 F. is preferred in many cases.

An element of the sulfur family, i. e., sulfur, selenium or tellurium, can be incorporated into the reaction product. This sulfur can be incorporated by adding elemental sulfur or a compound which yields sulfur, such as by treating the sulride-derived reaction product therewith, or treating a derivative of the sulfide-derived reaction product therewith.

In accordance with the invention, the resulting reaction mixture is treated with an amount of clay sufficient to improve or lighten the color thereof; generally this will be in the range of 1 4 to 10% by weight of the reaction mixture. The clay should contain not more than 6% by weight of water, and preferably 4% or less. A clay containing no water gives highly desirable results. However, in view of the relative cost of completely drying a usual clay, e. g., by heating, it is preferred for economic reasons to use a clay containing 4 to 6% of water. Although clay is preferred, other known decolorizing agents may be used. For example, activated alumina, which normally contains more than 6% water gives an improvement in decolorizing action when dried, as compared with the undried material.

The reaction mixture is mixed and heated with the decolorizing agent at a temperature in the range of F. to 500 F., preferably 250 F., and for a time in the range of 10 minutes to 10 hours, preferably one hour.

Then there is added thereto a filter-aid, e. g., a diatomaceous earth or silica product, such as .Celite or Dicalite Special Feed Flow in order to facilitate the filtration of the mixture. The filter-aid is not a decolorizing agent, and is'believed to be chemically inert in this system. Generally about 2% by weight of the filter-aid is used for this purpose. The mixture is then filtered, and the filtrate product which is obtained has improved color characteristics.

Any excess of a volatile reactant, or a volatile diluent, may be removed from the mixture by distillation. If desired, the final product may be solvent extracted with a suitable solvent, e. g., liquid propane, isopropyl alcohol, acetone, or other solvent known in the art.

The Sohio corrosion test and the engine performance characteristics of the improved additives of the invention are distinctly superior to those of products obtained by treatment with a clay containing a higher amount of water. This suggests that the water content of the clay is critical.

The amount of the final reaction product (i. e. the additive) to be incorporated in an oil or grease will depend upon the characteristics of the oil or grease and the intended use. Some oils have more of a tendency to corrode metals, or to form acids, sludges and lacquer deposits than others, and such oils require larger quantities of the addition agent. Also, oils that are intended for higher temperatures require larger amounts of the additive. In general, the range is from about to about 10%; under some circumstances, amounts as low as about 0.01% show a significant improvement. Since the provided reaction product is a lubricant, there isno upper limit. However, it may be uneconomical to include in the lubricant more of the provided reaction product than is necessary to impart the desired properties, such as 50%.-

The following examples and tests illustrate and point out advantages of the invention and also the criticality of the water content of the clay:

Example 1.Twenty parts by weight of P255 is mixed with such portion of 100 parts of a neutral diluent lubricating oil (15 lbs. per barrel acid treated lubricating oil stock having a viscosity of 225 SSU at 100 F.) as to form a slurry and this is mixed with a mixture of 25 parts of degras and 75 parts of the above described Paratcne. The balance of the 100 parts of the neutral diluent oil is added and the mixture agitated for one hour at 305 to 310 F.

The reaction mixture is divided into three parts, and each part is mixed with 4% clay by weight, for one hour at 250 F., using bone dry clay in Example 1(a).,'a clay containing *4 to 6% water :inEx-ample 1(b) and "clay containin 521% water in the comparative Example 1(0). 'The latter is a' typicalcommercial decolorizing clay after storage under commercial conditions. weight of a filter-aid is-added to each part, and the mixture filtered.

The optical density (appearance) and the sulfur content characteristics of the resulting filtrate "products are given in the following table:

These data show that the clay containing 4-6 water gives a higher optical density improvement ratio than either of the other clays used.

These data also show that the loss in sulfur L due to the clay treatment is related to the water content of the clay, the bone dry clay showing the lowest sulfur loss. The combined sulfur which is most susceptible to removal by water in this treatment appears to be most active as an inhibitor, as is shown below. In other words, not all of the sulfur therein is of equal inhibiting efiect. A special problem involved in this process is the improvement of the color of the product with a minimum of removal of the most active or hydrolyzable sulfur.

In the following tests, the "additives are prepared in a manner analogous to the foregoing,

and for convenience, the products analogous to the Example 1(a) materials are indicated as additives of Example 1(a) and 1(a) and those analogous to the comparative Example 1(0) are indicated as 1(0) and 1(0)".

Blendsof a conventional solvent extracted Mid- Continent lubricating oil base stock (SAE made in accordance with the invention were submitted to the known 10-hour Sohio corrosion test (described in Hughes et a1. U. S. Patent No. 2,464,233). The baseoil was identical in all runs.

The sulfur content characteristics of the filtrate products used therein are given in the following table:

TABLE IIA Example No Blank 1(a) 1(a) Percent water content of clay No clay. 0 21 Percent S content 4.20. 3. 74 3. ii

The test results in the following table are typical:

TABLE IIB Additive of Example No 1(a) 1(0) Percent combined sulfur in mixture 0.16 0.16 Amount of additive in percent by weight of mixture l 4. 27 5.14 Lacquer rat B Sludge rating A A- Viscosity increase (SUS) 95 126 Acid number 1. 2 1.74 Pentane insolubles l. 29 l. 74

The amount of the additive is selected so that each blend contains the same amount of com- Then 2% by bined sulfur: this :requires adding a higher amount of the additive of comparative Example 1(c) in view of the lower sulfurcontentthereof.

"This data clearlyshows 'the superiorityof the Example 1 (a) additive prepared in accordance with the invention as to all of-the indicatedcharacteristics. Since the amount of sulfur is the same in each mixture, it is evident that the particular combined sulfur removed from thecomparative Example 1(a)" additive is that type of combined sulfur which is most active as an inhibitor in the oil.

Oils containing addition agents of the invention have been evaluated by the so-called 36- hour-M Chevro'Iet engine test. The engineused is a conventional Chevrolet engine with 216.5 cu. in. piston displacement and a. compression ratio of 625 to 1. Prior to each testnew piston rings and two new copper-lead bearing inserts are installed. The engine-is operated at 3150 R. P. M. with aload of B. H. P. and at atomperature at the jacket outlet of 200 F. The' -lubricatingoil temperature is maintained at 265 Fjforan S. A. 10 grade oil, and at 280 F. i'or oils of S. A. E. 30 to grades. The "fuel used contains from 2.5 to 3.0 m1. tetraethyl lead per gallon. Besides the weight loss of the test bearings, deposits in the power section, and -proper-' ties er the used oil, sampled'near the middle-and also at the end of the test, are examined.

For comparative purposes, the test values :ior varnish rating, piston skirt, acid number, pentane insolubles, and /100-the viscosityincrease are added; the sum multiplied by '10, and divided by the'number of'hour's-the test is run. The resulting value is termed the Demerit Rating.

A conventional "solvent extracted Mid-Continentlubricatin'g oil base stock "(8. A. E. 20) and blended compositions of this 011- made in accordance with the invention were submitted to tests in accordance with this procedure. The base oil was identical in an runs. The results in the 'fol lowing table are typical: I

TABLE III Additive of Example No 1(a) 1(a) Amount of additive in percent by weight ot-mixture 4.28 5. 12 Varnish rating. 41. 32. 75 Piston skirt rating 6.75 '5. 00 Sludge rating".-. 44. 00' '43. 25 Overall rating..-. 85. 75 76.00 Viscosity Increase (SSU) 112 148 Acid number i 0. 8 l. 1 Pentane insolubles 2. l4 2. 87 Demerit rating 6. 4 9. 4 Corrosion oi Cu-Pb bearing met mg t.

loss per bearing half-shell) 52 The amount of the additive is selected so that each mixture contains the same amount of combined sulfur; this requires adding a slightly higher amount of the additive of Example 1(0) in view of its lower sulfur content.

The markedly higher varnish rating characteristic of the oil containing the Example 1(a) additive is indeed striking. Since, in preparing this additive a. bone dry clay is used, it appears that the particular combined sulfur removed by the treatment with clay containing a. relatively high amount of water, such as that of Example 1(0), is that type of combined sulfur which is most effective in inhibiting varnish formation in the engine. In addition, the oil containing the Example 1(a) additive shows better sludge rating, and overall rating. The corrosion characteristics of the Example 1(a) additive are markedly superior, and its demerit rating is distinctly lower than that of the oil containing the comparative Example 1(0) material.

Improved hydrolyzable sulfur type additives are obtained in accordance with the invention, following the above procedures, except replacing the degras by another oxygenated compound;

Example 2.-Myristic acid.

Example 3.-Spermafol No. 52 (a hydrogenated sperm oil having an iodine value of 6 to '7, a melting point of 50-52 C., a free fatty acid content (as oleic) of 1 to 2%, a saponification value of 135-138).

Example 4.-Alox No. 152 (an oxidation product of paraffin wax, including a mixture of alcohols, acids, ketones and other oxidation products of paraffin, as described in U. S. Patent No. 2,419,325).

Example 5.-(CH31)2CO, available commercially under the trade name Palmitone.

Example 6.-Lauryl alcohol.

Comparable results are obtained following the above described procedures, except using another polyolefin, or another oxygenated material, or another phosphorus sulfide, or mixtures thereof, to produce improved hydrolyzable sulfur type additives as discussed hereinbefore; and in view of the foregoing descriptions, the art will clearly understand the invention in its broad aspects including modifications and variations thereof.

If desired, the additives of the invention may be used together with the other oil addition agents, e. g. pour point depressants or film strength agents. In some instances, it is desirable to include in a lubricating oil containing the additive an agent for improving the clarity of the oil, e. g., lecithin, lauryl alcohol, and the like, which are known to the art. In order to prevent foaming of the oil containing a small proportion of the additive, it is desirable in some cases to add a very small amount of tetra-amyl silicate, an alkyl ortho carbonate, ortho formate or ortho acetate, or a polyalkylsilicone oil, which prevent foaming upon the bubbling of air through oil containing a few per cent of the additive.

It is intended to claim the invention broadly,

except as limited by the following claims.

products of 5 to by weight-of a phosphorus sulfide and to 40% of a mixture of one part by weight of an oxygen-containing organic compound reactive with phosphorus sulfide and selected from the group consisting of those com? pounds containing hydroxy, carbonyl, ether and carboxy radicals, and having a boiling point of at least 225 F. with 1 to 10 parts of a poly-olefin capable of improving the viscosity index characteristic of a lubricating oil, reacted together at a temperature in the range of 225 to 500 R, which method comprises treating such reaction products with an amount of adsorbent decolorizing agent in the range of 1 to 10% by weight of the reaction mixture and suilicient to improve the color of the reaction product, said decolorizing agent having a water content in the range of 0 to 6% by weight, and recovering improved reaction product.

2. The method of claim 1 wherein the polyolefin is of about 10,000 average molecular Weight.

3. The method of claim 1 wherein the phosphorus sulfide is P285 and the decolorizing agent is clay.

4. The method of claim 3 wherein the polyolefin is of about 10,000 average molecular eight.

5. The method of claim 4 wherein the oxygencontaining organic compound contains a carbonyl group.

6. The method of claim 5 wherein the carbonyl oxygen-containing organic compound is an ester.

'7. The method of claim 6 wherein the ester is degras. v I 4 S. The method of claim '7 wherein the clay contains 4 to 6% of water.

JOHN D. BARTLESON.

'References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,386,952 Hughes Oct. 16, 1945 2,480,296 Burk Aug. 30, 1949 2,494,592 Smyers Jan. 17, 1950 OTHER REFERENCES "Acid-Treated Clays by B. A. Stagner; The Science of Petroleum, Oxford Press 1938, vol.

III, pgs. 1703-1704. Copy in Div. 31. 

1. A METHOD OF IMPROVING THE COLOR OF LUBRICANTS AND LUBRICANT ADDITIVES WHICH ARE REACTION PRODUCTS OF 5 TO 60% BY WEIGHT OF A PHOSPHORUS SULFIDE AND 95 TO 40% OF A MIXTURE OF ONE PART BY WEIGHT OF AN OXYGEN-CONTAINING ORGANIC COMPOUND REACTIVE WITH PHOSPHORUS SULFIDE AND SELECTED FROM THE GROUP CONSISTING OF THOSE COMPOUNDS CONTAINING HYDROXY, CARBONYL, ETHER AND CARBOXY RADICALS, AND HAVING A BOILING POINT OF AT LEAST 225*F. WITH 1 TO 10 PARTS OF A POLY-OLEFIN CAPABLE OF IMPROVING THE VISCOSITY INDEX CHARACTERISTIC OF A LUBRICATING OIL, REACTED TOGETHER AT A TEMPERATURE IN THE RANGE OF 225* TO 500* F., WHICH METHOD COMPRISES TREATING SUCH REACTION PRODUCTS WITH AN AMOUNT OF ADSORBENT DECOLORIZING AGENT IN THE RANGE OF 1 TO 10% BY WEIGHT OF THE REACTION MIXTURE AND SUFFICIENT TO IMPROVE THE COLOR OF THE REACTION PRODUCT, SAID DECOLORIZING AGENT HAVING A WATER CONTENT IN THE RANGE OF 0 TO 6% BY WEIGHT, AND RECOVERING IMPROVED REACTION PRODUCT. 